I’m just curious as to the process and behavior of the surface temp of a shuttle once there’s virtually no particles in contact with the craft.
I’m aware space is cold due to the absence of matter,
But does a space shuttle take a much longer time frame to cool down with less matter available to transfer the heat of the craft to, or does the lack of matter cause the shuttle to cool rapidly?
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Spacecraft don’t get really hot during launch, it’s only during reentry that serious heating occurs. During launch, by the time the spacecraft is going fast enough to generate serious heat, it’s already cleared the densest part of the atmosphere.
At an rate, infrared radiation is the only means of heat transfer in space, and it’s the least efficient of the 3 methods of heat transfer, which is why spacecraft have radiators to help shed waste heat but also thermal insulation to protect them from the cold. Without these, they would overheat from their own internal parts generating heat and from solar radiation, and also become too cold to operate, depending on which side of the spacecraft is facing the sun and whether the spacecraft is exposed to sunlight or not.
Yes, it’s much harder to radiate heat in space. In atmosphere, air circulates near a hot object via convection, and rapidly brings the temperature down by constantly bringing in room temperature air into contact with the object to help cool it down.
In space, the main way of cooling is essentially by emitting light (black body radiation). Normally super hot objects start to glow, but when they are at lower temperature it’s emitting light too, just not visible light. This carries a tiny amount of energy away, cooling it down. Exactly how fast depends on the material, and the space shuttle has very fast dissipating materials.
However, the surface of the space shuttle is probably not as hot as you think. It can’t take off too fast and gains a lot of its speed outside of atmosphere so air friction is not a significant concern compared to reentry, where you are at hypersonic speeds. The heat generated during reentry is orders of magnitude higher.
Space is called cold because the temperature of the cosmic microwave background (basically the energy coming from in between all the stars) is very low. But because there’s so little matter at orbital altitude and even less the deeper you go into space, there’s a considerable insulating effect. You can’t use conduction or convection to get rid of heat, so you can only radiate it. That means objects in space tend to take a long time to cool down, or since we’re in a solar system, may actually heat up to a failure point just because of the sun.
Heat management is a critical component of spacecraft design. Since you mentioned the shuttle, it had advanced materials that were designed to shed heat extremely quickly. I don’t know if they were as effective in space as they were as a reentry heat shield, but in general yes, you want as much ability to radiate excess heat as possible.
>I’m aware space is cold due to the absence of matter
The concept of “temperature” does not make any sense of a near-vacuum. Temperature is a **characteristic of matter**. A vaccuum has no temperature. And for a near-vacuum with only a handful of hydrogen atoms bouncing around it makes absolutely no difference whether those few atoms have a temperature of -270°C or 30,000°C. There’s still next to no thermal energy in that bit of space.
>I’m just curious as to the process and behavior of the surface temp of a shuttle once there’s virtually no particles in contact with the craft.
>But does a space shuttle take a much longer time frame to cool down with less matter available to transfer the heat of the craft to, or does the lack of matter cause the shuttle to cool rapidly?
Spacecraft are notoriously difficult to **cool**. You can’t dump excess heat anywhere because there is no matter around you into which you could transfer it. The only way is to use heat radiation and that requires massive radiators.
Losing heat is hard in space as you mentioned. Because of the heat from sunlight, electronics, propulsion and other spacecraft system, the spacecraft needs a way to lose the heat that accumulates, because there is no air to give that heat so it stays in the spacecraft.
All spacecrafts have radiators to lose the heat by radiation, they usually are white/grey panels. The American Space Shuttle had its cargo bays doors opened during the whole mission because its radiators are located on the inner part of the doors.
If these doors remained closed in space, the shuttle couldn’t lose enough heat compared to what it receives and produce, so everything would be cooked inside.
To quote Wikipedia [https://en.wikipedia.org/wiki/Heat_transfer](https://en.wikipedia.org/wiki/Heat_transfer)
>Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes.
Conduction, thermal convection, and transfer of energy by phase changes do need matter but thermal radiation does not. The visible and invisible light we get from the sun is thermal radiation.
Everything warmer than absolute zero emits thermal radiation. Most stuff we are used to including us is at a temperature so the thermal radiation is in the infrared range (IR). We can see it without the naked eye but a thermal camera can. You can feel IR radiation from the warm but not glowing objects when it heats up your skin.
The way the space shuttle and ISS get rid of heat is with radiators. On the space shuttle, they are on inside of cargo bay doors http://www.projectrho.com/public_html/rocket/images/basicdesign/shuttleHeatRadiator.jpg Overheating because of sunlight is a major concern for the shuttle so opening the cargo bay doors was one of the first thing done when it was in orbit.
ISS have large radiators that typically are close to perpendicular to the sunlight so they are as efficient as possible https://letstalkscience.ca/sites/default/files/styles/x_large/public/2019-12/Heat_Rejection_System_radiators.jpg?itok=JROfS9Pf
The system works like any other refrigeration system like a fridge or an AC but is shaped to optimize cooling from radiation instead of contact with air. The result is large flat areas to radiate the energy to space. If you use air you have large area too but in may stacked layers so blowing air with a fan is simple
It will still cool quite quickly. This is because the heat will escape as radiation, even when there are no particles nearby.
Interesting since most sci-fi would have you believe as soon as you enter space – instant ice cube. Abandoned ships are always frozen tombs no matter if they are running or not.
Think of space as nature’s Yeti mug.
In both cases, the vacuum insulates one component from another component.
Since the shuttle and crew generate heat, it’s difficult to get rid of that heat without dedicated components.
The systems on board naturally give off heat – this article is pretty interesting on this issue:
[https://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1#:~:text=The%20heated%20ammonia%20circulates%20through,made%20of%20honeycomb%20aluminum%20panels](https://science.nasa.gov/science-news/science-at-nasa/2001/ast21mar_1#:~:text=The%20heated%20ammonia%20circulates%20through,made%20of%20honeycomb%20aluminum%20panels).
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